This section provides background information related to the present disclosure which is not necessarily prior art.
It is widely known in an automotive vehicle engine to transfer a portion of the engine output to a plurality of belt driven accessory components utilizing an endless serpentine belt. Typically, each belt driven accessory component includes a pulley drivingly engaged with the belt and the belt is driven by an output pulley coupled directly to the crankshaft.
Internal combustion engines operate as a pulse system, constantly accelerating and decelerating and causing engine vibrations. As a result of these changing speeds, the belt driven accessory components, which are driven by the crankshaft, are continually trying to speed up and slow down. This can result in unacceptable levels of noise and vibration along with reduced accessory drive component durability due to high fluctuating loads and vibrations. Additionally, rapid engine accelerations and deceleration, such as during transmission shifts and engine startup and shutdown, cause belt squeal from slippage between the belt and the pulley as well as heavy impact loading on the belt.
It is known to provide a decoupler assembly between the belt driven accessory component and the pulley to allow the belt driven accessory component to operate temporarily at a higher speed or “overrun” the pulley as the pulley oscillates with the speed of the engine. Examples of such decouplers are disclosed in the U.S. Pat. No. 6,083,130, issued to Mevissen et al. on Jul. 4, 2000 and the U.S. Pat. No. 5,139,463, issued to Bytzek et al. on Aug. 18, 1992.
It is also known to provide a decoupler assembly between the belt driven accessory and the pulley to isolate vibrations therebetween and allow overrunning, reducing noise and impact loads. An example of such a decoupler is disclosed in U.S. Pat. No. 6,044,943 issued to Bytzek et al. on Apr. 4, 2000.
However, it remains desirable to provide an improved decoupler assembly.